The present invention relates to improvements in diaphragm coupling or interlock devices for use in an interchangeable lens type camera, by which the aperture value set by the lens diaphragm setting member which operates to preset the diaphragm aperture in the interchangeable lens, is transmitted to an exposure control mechanism located in the camera body.
Among the known interlocking devices of the present type is one which is provided with a coupling element secured to a diaphragm setting ring which is rotatable relative to the interchangeable objective lens barrel, and a pantograph mechanism which may be interlocked with the coupling element, or one which is provided with a pin engageable with the coupling element and an arcuate rail concentric with the center of rotation of the coupling element.
However, both the pantograph mechanism and the arcuate rail occupy considerable space, and thus considerably increase the size and bulk of the camera. In addition, great difficulties are encountered in the connection of an exposure control mechanism which is mounted in a finder casing removable from a camera body. Furthermore, the pin engaged with the rail has to slidingly rotate relative to the camera body or relative to the finder casing on the camera body, so that a smooth rotation in association with the movement of the diaphragm setting ring is not achieved.